MEOSAR Performance and Moving BeaconsSAR Controllers Workshop 2019

March 5 – 7, 2019

Jesse ReichNOAA/SARSAT

Ground Systems Engineer

Introduction

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Suspect AlertsMEOLUT Accuracy

EOC vs IOCMoving BeaconsComposite vs elementalsImproving Performance

MEOLUT UpgradesPhased Array MEOLUTCommissioning Other MCCs

Future WorkUAVs BuoysNetworking

• MEOLUT vendor identified one fix and implemented in Spring 2018

• Approximately 2 “suspect” alerts are being distributed daily to RCCs, down from 5 per day

• Other ideas for reducing the amount of suspect alerts have been considered but at this time, the rate seems manageable.

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Suspect Alerts

MEOLUT Accuracy

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On 13 December 2016 the Cospas-Sarsat system entered the Early Operational Capability (EOC) for the MEOSAR System

The MEOLUT location accuracy requirements for EOC are:▪ Single burst: 70% within 5 km; and 90% within 10 km▪ Multiple burst: 95% < 5 km and 98% < 10 km, within 20 minutes

Location accuracy requirements for Initial Operational Capability/ Full Operational Capability (IOC/FOC:▪ Single burst: 90% within 5 km (no 10 km criteria)▪ Multiple burst: 95% < 5 km and 98% < 10 km, within 10 minutes▪ Slow Moving beacons (0.5 to 10 m/s):

▪ Single burst: 70% within 10 km, 95% within 20km ▪ Multiple burst: 75% within 5 km, 95% within 7 km, within 10 minutes

The US MEOLUTs are currently meeting the EOC location accuracy requirements and in most cases the IOC/FOC requirements for static beacons

Moving Beacons

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Based on real-world cases, tests and analysis, location accuracy is degraded for beacons that are moving. How degraded? The issue is acknowledged and the international community has agreed it must be addressed before moving to IOCThe USA SARSAT Program, has been actively studying the issue and ways to mitigate it. NASA SARLAB has conducted various moving beacon tests using UAVs as platforms. Engaged with the MEOLUT vendor and consultants on different algorithms that can be employedInternational Partners have done a great deal of work as well on the issue

Improvements in Performance

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Recent upgrade to FL MEOLUT to process Second Generation Beacons has also led to improvement in First Generation Beacon detection and location accuracy. HI MEOLUT to receive upgrade in the next two weeks. Aging LEOLUTs were replaced with LEO/MEOLUTs to provide additional MEOSAR data when not tracking LEOSAR satellites NOAA contracted with AGI and Orbit Logic to provide scheduling software that maximizes coverage of the US AOR. The USMCC is completing the project to generate and send integrated tracking schedules to the MEOLUTs The MEOLUT contractor has committed to meeting more stringent Time of Arrival / Frequency of Arrival (TOA/FOA) measurement accuracy requirements. NOAA has contracted for acquisition of a new phased array MEOLUT to be installed at Holloman AFB, New Mexico in April 2020USMCC working diligently to get other MCCs commissioned as “LGM” or LEO/GEO/MEO, so that they can send MEO data operationally.

Additional Future Improvements

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The MEOLUT contractor will implement updated location algorithms to better address moving beacons and meet the IOC/FOC requirementsCanada will be installing phased array MEOLUTs from the same vendor. There is a bilateral working group established to harmonize designs and eventually network MEOLUT dataWhen Australia MCC (AUMCC) is LGM commissioned, data can be networked from the Australian and New Zealand MEOLUTs. NOAA is in discussions with the National Data Buoy Center to deploy reference beacons on buoys to gauge system performance and provide reference / calibration data. And… Second Generation Beacons

Composite versus Elemental Solutions

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The USMCC generates and updates a confirmed or composite location for each site, when corroborating data has been received. In LEOSAR era, this was referred to as a “resolved” location. RCCs receive this composite (when available) but will also receive “elemental” locations at times. There are various criteria that result in the MCC sending an updated location containing elementals. At times these elementals may be less accurate due to the timing of when they are sent

Supplemental Slides

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Machine Learning

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● Red: > 10 km ● Black: 5 – 10 km● Blue: 2 - 5 km● Green: ≤ 2 km● Orange: Ground Truth location

Classifying MEOLUT solutions of a real SAR case using a Random Forest Classifier

Moving Beacon Study Lake George

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A PLB was used for a series of tests on and around Lake George in upstate New York (7943 km from Hawaii, 2080 km from Florida, location is 43.493, -73.63) The results appear typical of MEOSAR performance during moving beacon events.Focus on Config #1 and #5

Location # locations ave # <5 km % < 5

km# < 10

km% < 10

km# < 20

km% < 20

kmmedian

(km)75% (km)

90% (km)

95% (km)

Config # 1 - Slow speed – Boat 399 7.71 132 0.33 301 0.75 383 0.96 6.73 9.92 13.17 18.59

Config # 2 - High speed – Hand 25 19.73 2 0.08 5 0.2 23 0.92 12.48 14.31 15.89 68.72

Config # 3 - Bobbing Dock 155 2.62 146 0.94 155 1 155 1 2.26 3.32 3.76 5.08

Config # 4 - Bobbing Morring 1583 2.29 1497 0.95 1571 0.99 1576 1 1.83 2.65 3.89 5.2

Config # 5 - Slow speed – Hand 64 11.04 22 0.34 38 0.59 53 0.83 6.97 16.76 21.71 34.74

Config # 6 – Hike 231 7.13 127 0.55 185 0.8 220 0.95 4.41 8.97 14.91 19.85Config # 7 - Fixed Dock 538 1.75 518 0.96 537 1 537 1 1.42 2.2 3.1 4.56

Config #1

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Config #5

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